As others mention, the language itself isn't that important. Like so many other languages e.g. Python, it is basically a Lisp underneath a layer of infix synta

As others mention, the language itself isn't that important. Like so many other languages e.g. Python, it is basically a Lisp underneath a layer of infix syntax. Most of the work went into what in Python terms would be called the standard library, which includes a stupendous amount of scientific and mathematical code, a lot of which is not so easy to implement.